Ocean Science www.ocean-sci.net 1812-0784 1812-0792 6 1 2010 10.5194/os-6-345-2010 http://www.ocean-sci.net/6/345/2010/ http://www.ocean-sci.net/6/345/2010/os-6-345-2010.html http://www.ocean-sci.net/6/345/2010/os-6-345-2010.pdf 345 359 2010-03-08 Malvinas-slope water intrusions on the northern Patagonia continental shelf A. R. Piola apiola@hidro.gov.ar N. Martínez Avellaneda R. A. Guerrero F. P. Jardón E. D. Palma S. I. Romero Departamento Oceanografía, Servicio de Hidrografía Naval, Buenos Aires, Argentina Departamento de Ciencias de la Atmósfera y los Océanos, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina Institut für Meereskunde, KlimaCampus, Universität Hamburg, Hamburg, Germany Instituto Nacional de Investigación y Desarrollo Pesquero, Mar del Plata, Argentina Laboratoire d'Océanographie et du Climat, Université de Paris VI, Paris, France Departamento de Física, Universidad Nacional del Sur, Bahía Blanca, Argentina Instituto Argentino de Oceanografía, CONICET, Bahía Blanca, Argentina The Patagonia continental shelf located off southeastern South America is bounded offshore by the Malvinas Current, which extends northward from northern Drake Passage (~55&deg; S) to nearly 38&deg; S. The transition between relatively warm-fresh shelf waters and Subantarctic Waters from the western boundary current is characterized by a thermohaline front extending nearly 2500 km. We use satellite derived sea surface temperature, and chlorophyll-<I>a</I> data combined with hydrographic and surface drifter data to document the intrusions of slope waters onto the continental shelf near 41&deg; S. These intrusions create vertically coherent localized negative temperature and positive salinity anomalies extending onshore about 150 km from the shelf break. The region is associated with a center of action of the first mode of non-seasonal sea surface temperature variability and also relatively high chlorophyll-<I>a</I> variability, suggesting that the intrusions are important in promoting the local development of phytoplankton. The generation of slope water penetrations at this location may be triggered by the inshore excursion of the 100 m isobath, which appears to steer the Malvinas Current waters over the outer shelf. Acha, E. M., Mianzan, H. W., Guerrero, R. 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